In proteomics and other similar types of experiments chemical noise or background ions (often of unknown origin) can inadvertently be counted or treated as analyte data and can cause lower scores or even false positive identifications when library searching from either MS and/or MS/MS data.
Some of the chemical “noise” comprises multiply charged clusters adducted to the analyte peptides. Multiply charged parent or precursor adduct ions may be present as well as fragment ions from such clusters. The cluster adduct ions may originate from solvents.
US 2012/303288 (Morinaga) discloses a data analysis method in which clustering is performed on standardised intensity values peaks such that isotope peak groups and adduct ion peaks derived from the same substance but having different mass to charge ratios values are placed together in the same clusters. Clusters that are considered redundant are removed.
It is desired to provide an improved method of mass spectrometry.